1. Field of the Invention
The present invention relates generally to an apparatus and method for cleaning a substrate in a printing apparatus, and more particularly to an apparatus and method for cleaning a substrate without excessively affecting uniform motion of the substrate in a manner that would impair image quality.
2. Discussion of the Related Art
A typical document copier includes an electrostatic printer having a belt with a photoconductive surface. To transfer an image onto a sheet of paper, the printer charges the belt to a uniform potential, and then selectively exposes the belt to a pattern of light corresponding to the image. The light discharges parts of the belt resulting in a pattern of charge corresponding to the image, an electrostatic latent image, being formed on the belt. The portion of the belt having the electrostatic image then passes a development station that deposits toner on the belt in the pattern of the image, resulting in a developed image. A sheet of paper is then tacked onto the belt and removed from the belt, resulting in the image being formed on the paper.
A proposed electrostatic printer includes a cleaning station downstream from the development station. The cleaning station removes residual toner from the belt. The cleaning station includes a cleaning blade for scraping toner from the belt.
The surface of the belt of the proposed printer typically has a seam spanning the width of the belt. The cleaning blade passing over the seam results in a disturbance in uniform motion of the belt, which can impair image quality if the disturbance occurs while an image is being developed as described above. Further, the cleaning blade passing over the seam results in mechanical stress being placed on the blade, reducing the life of the blade.
Problems caused by these variations in belt motion are exacerbated in single pass full color printers, which require especially accurate placement on the belt of overlying multiple images corresponding to each color component.